J 191 
12 W5 
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THE EFFECTS OF KEROSENE AND OTHER 

PETROLEUM OILS ON THE VIABILITY 

AND GROWTH OF ZEA MAIS 



BY 



JOHN HAMILTON WHITTEN 

A.B., University of Illinois, 1911 
A.M., University of Illinois, 1912 



THESIS 

Submitted in Partial Fulfilment of tne Requirements for the 

Degree of 

DOCTOR OF PHILOSOPHY 
IN BOTANY 

IN 

THE GRADUATE SCHOOL 

OF THE 

UNIVERSITY OF ILLINOIS 
19 14 




-<H 






THE EFFECTS OF KEROSENE AND OTHER 

PETROLEUM OILS ON THE VIABILITY 

AND GROWTH OF ZEA MAIS 



BY 



JOHN HAMILTON WHITTEN 

A.B., University of Illinois, 1911 
A.M., University of Illinois, 1912 



THESIS 

Submitted in Partial Fulfilment of tke Requirements for th< 

Degree of 

DOCTOR OF PHILOSOPHY 
IN BOTANY 

IN 

THE GRADUATE SCHOOL 

OF THE 

UNIVERSITY OF ILLINOIS 
19 14 



623 i9i 



Bulletin of the Illinois State Laboratory of Natural History. 
Vol. X, Art. V. 



!). OF 3, 

MAR 9 1915 



CONTENTS 



I. Introduction 7.45 

II. Methods .246 

1. Elimination of the oil 246 

2. Soaking in water 247 

3. Moisture content of the soil 247 

4. Culture media 247 

5. Preparation of the soil 248 

6. Planting 249 

7. Temperature 250 

III. Experimentation and discussion 250 

1. Effects of the period of immersion and the moisture content of the soil. . .250 

2. Long periods of immersion 255 

3. Types of abnormalities 256 

4. Dry membranes 258 

5. Mutilated membranes 260 

6. Moisture content of the grains 264 

7. Variation in soil moisture 266 

8. Other oils . ; 269 

9. Summary of conclusions . . ; .... 271 

Bibliography 272 

Vita 



Digitized by the Internet Archive 
in 2010 with funding from 
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http://www.archive.org/details/effectsofkerosenOOwhit 



Article V. — The Bffects of Kerosene and other Petroleum Oils 
on the Viability and Growth of Zea mais. By John H. Whitten, 
Ph.D. 



I. Introduction 

It has long been a custom among farmers to pour kerosene over 
seed corn just previous to planting in order to protect it from being 
injured or destroyed by squirrels, crows, or other pests. Until recent- 
ly few or no careful observations had been made to determine whether 
the treatment accomplished the purpose for which it was used or if 
the effects on germination and subsequent growth were favorable or 
otherwise. 

Lummis ('03), from a few preliminary experiments in field and 
laboratory, reported a decided reduction in the percentage of germina- 
tion and a very conspicuous injury to growth. Forbes ('08), seeking 
a repellent particularly against the corn root-aphis, gave the kerosene 
treatment a much more extensive trial. He found it very effective 
in repelling the corn-field ant and consequently in controlling the aphis, 
but he reports the frequent occurrence of "perplexing discrepancies" 
in respect to the effects of the treatment on germination and growth. 
His data show that in some instances corn was very markedly injured, 
while in others a similar treatment produced no detrimental effect; 
and that a brief treatment — thirty minutes' immersion — was more in- 
jurious than one of twenty days. Having no explanation for such re- 
sults and not desiring to enter into the analysis of a complex problem 
of plant physiology, Professor Forbes abandoned the use of kerosene, 
but he was free to admit that the scope of his investigations was too 
limited to warrant general conclusions. 

Duggar and McCool ('09), issued a circular of information in- 
tended especially for the constituency of the Cornell University Ex- 
periment Station. In this report the authors made no pretension to 
original investigation on the use of kerosene as a deterrent. They 
laid particular stress on Professor Forbes's work and made their rec- 
ommendations accordingly. 

Previous to the publication of the bulletin above cited there had 
been some work done on the same subject under the direction of 
Dr. Hottes in the laboratory of plant physiology at the University of 

A thesis submitted in partial fulfilment of the requirements for the 
degree of Doctor of Philosophy in Botany in the Graduate School of the 
University of Illinois, 1914. 



246 

Illinois. This work was not completed, but from the results obtained 
and from the report published by Professor Forbes, Professor Hottes 
was led to believe that the physiological aspects of the subject were 
of sufficient interest to warrant a more thorough investigation, and it 
was at his suggestion and under his direction that the work herein 
described was undertaken. It is with pleasure that I acknowledge the 
helpful advice and constructive criticism offered by Professor Hottes 
during the progress of the work. 

II. Methods 

In a series of initial experiments an attempt was made to learn 
something of the conditions which affect the germination of corn after 
immersion in kerosene, and thus to discover, if possible, the causes of 
the "perplexing discrepancies"referred to by Professor Forbes. Very 
early in this work it became apparent that the highest per cent, of 
germination could be secured only when the oil on the surface of or 
within the grain had been reduced to the minimum. The effect of the 
oil became especially marked when the corn was placed under condi- 
tions for germination with more than the usual amount of water pres- 
sent. These preliminary experiments further showed that the pres- 
ence of water in the grain at the time of immersion in kerosene was 
responsible in no small degree for the wide variation in the per cent, 
of germination. 

I. ELIMINATION OF THE OIIv 

The superficial oil was removed from the grains by careful wip- 
ing with soft, absorptive towels immediately after removing them 
from the kerosene. The grains were then imbedded in desiccated 
powdered clay or plaster of Paris to remove as much of the remain- 
ing oil as possible. The same result was accomplished, and much more 
simply, by placing the corn on dry filter-paper exposed to the air to 
allow the kerosene to volatilize. In a few instances when the corn had 
been immersed for long periods of time the gummy coating formed on 
the outside of the grain was dissolved off by washing vigorously for 
a few minutes in chloroform. Acetone was also tried for the same 
purpose, but it proved to be injurious to control grains and its use was 
discontinued. Since exposure to dry air at room temperature, 23 to 
28 degrees C, gave results in no wise inferior to the other methods 
used for eliminating kerosene, it was used almost exclusively in all 
cases where the elimination of the oil was called for. 



247 



2. SOAKING IN WATER 

Grains which had been immersed in kerosene were soaked in 
water for from one to forty-eight hours and then placed, together with 
a check, under the usual conditions for germination. It was found 
that soaking in running water for periods of from one to eight hours 
was not injurious and in a few instances seemed slightly beneficial. 
When soaked for longer periods a decided reduction in the per cent, 
of germination was manifested. Abnormalities in the later growth of 
the seedlings from grains immersed in kerosene and subsequently 
soaked in water for the shorter periods were more frequent than from 
unsoaked grains. On the whole it seemed clear that the smaller the 
amount of water present in the grain at the time of planting and con- 
sequently the more slowly the growth processes were initiated the less 
serious were the effects of the kerosene. 

3. MOISTURE CONTENT OF THE SOIE 

The moisture content of the soil was varied from the minimum 
amount necessary for germination to complete saturation. The re- 
sults were so diverse that it was decided to make three sets of tests 
identical in every way except the water content of the soil, lhe first 
contained approximately the minimum amount in which germination 
would take place readily; the second, the maximum amount in which 
germination and normal growth of control grains could be secured; 
and the third, an amount which represented an approximate mean to 
the other two. Different soils vary so widely in their power to hold 
water that the percentages of saturation used to secure the conditions 
indicated above must necessarily be determined by experiment and can 
only be made to apply to the particular soil used. 

4. CULTURE MEDIA 

The grains were germinated in the ordinary germinating pans, in 
yellow clay, sand, sawdust, black loam, and in various mixtures of 
sand and sawdust and of sand and black loam. Of these the sawdust 
was the only one which showed any harmful effects. The use of the 
germinating pan was early discontinued because of the necessity ot 
making observations on the growth for some time following germina- 
tion A mixture of black loam and sand yielded as good results as 
any other, and this was selected because of its adaptability for vary- 
ing and maintaining the moisture content. 



248 



5- PREPARATION OF THE SOIL, 

A quantity of potting soil, a very rich black loam, was obtained 
from the university greenhouse. It had been prepared by piling up 
turf and allowing the vegetable matter to decompose. After drying 
to a sufficient degree to render it suitable for handling, the soil was 
screened through a sieve with one-twelfth inch mesh and mixed with 
sand, similarly screened, in the proportion of two parts of loam to 
one part of sand. These two constituents were worked into a per- 
fectly homogeneous mass, and its capacity for holding water was 
determined by the following method : 

A cu. dm. of the prepared soil, which weighed I kilo, was dried 
to constant weight in an oven at ioo degrees C. After the constant 
weight had been secured, the dry soil was placed on filter-paper in a 
funnel and water was added in small quantities at frequent intervals. 
When the soil was uniformly moist and no longer increased in weight 
after the surplus water had drained off, it was again weighed, and thus 
the quantity of water necessary to saturate was determined. Soil in 
this condition was considered to be 100% saturated. The different 
percentages of saturation used were computed on the basis of the total 
amount of water in the saturated soil. 

The following table shows the records of a few typical tests made 
to determine the capacity of the soil for holding water. 



Wt. of norm, 
soil 


Wt. of dry 
soil 


Wt. of H 2 

in norm. 

soil 


Wt. of sat. 
soil 


Wt. of H 2 

in sat. 

soil 


% of sat. 

of norm. 

soil 


1020 

1000 

1000 

938 


943 
928 
924 
851 


77 
72 
76 
87 


1302 
1253 
1262 
1201 


359 
325 
338 
350 


21 
22 

22 

24.8 



By exercising a little care, the moisture content of the soil could 
be adjusted at the beginning of each test so that one cu. dm. of soil 
would weigh i kilo. This was selected as the standard weight and 
somewhat arbitrarily designated as "normal soil." 

The difference between the weight of the normal soil and the 
weight of the dry soil is the weight of the water in the normal soil. 

The difference in the weights of the dry and the saturated soils 
is the weight of water necessary to produce 100% saturation. Know- 
ing these facts it becomes a simple matter to add water to the normal 
soil in quantities required to make it any desired per cent, of satura- 
tion. 



249 

The same soil was used repeatedly, but it was carefully screened 
and brought to "normal weight" before using. 

When a 30% saturation or less was desired, it was possible to 
mix thoroughly the soil and the required amount of water without 
puddling. Soil containing higher percentages of saturation could not 
be prepared in this manner. The most convenient and efficient way of 
securing a rapid and an equal distribution of the water in 50 and 75% 
saturations was to place a thin layer of soil in the pan and spray it 
with the proportionate amount of water, then add another layer and 
spray again. This process was continued until the desired amount of 
soil was in the pan and the proper amount of water added to give the 
required moisture content. In a soil thus treated and protected to 
avoid evaporation, the moisture was found uniformly distributed in 
a short time. 

6. planting 

The grains were planted in rectangular pans 35 cm. by 20 cm. 
and 7 cm. deep. These pans were provided with closely fitting covers 
in which were openings for aeration. 

Each pan was furnished with 4 cu. dm. of prepared soil, in which 
the grains were planted and then uniformly covered with an additional 
cu. dm. of soil. The grains were placed one-half inch apart in rows 
one inch apart. As an aid in securing an equal distribution and thus 
in observing the behavior of the individual grains, a wire netting with 
one-half inch mesh was placed on the surface of the soil and the grains 
were inserted through it at regular intervals. They were thrust into 
the soil in an upright position until the butts were flush with the sur- 
face, and were then covered with the final cu. dm. of soil. To prevent 
the grains from being pushed out of the loose soil of the low moisture 
cultures by the growth of the root, the soil was slightly compressed by 
placing a glass plate on the surface and applying a slight pressure with 
the hand both before and after the addition of the soil used for cover- 
ing. 

The gross weight of the pan and contents was then taken. The 
pans used were provided with a shoulder just beneath the cover which 
served to support a wire netting on which was kept moist blotting 
paper. In this way the loss of water was greatly reduced, amount- 
ing to only 2 or 3 c.c. in twenty-four hours. The original weight was 
kept constant by the addition of water each morning by means of an 
atomizer. 

The pans were kept covered during the period of germination 
and until the seedlings were well through the soil. The critical period 
of the test then being passed, the covers were removed to admit light, 



250 

and no further effort was made to keep the moisture content constant. 
Water was added in sufficient quantities to keep the corn in good 
growing condition. 

The method used for securing and maintaining the moisture con- 
tent of the soil is not absolutely accurate. The limits of error, how- 
ever, were certainly within 2%, which was sufficiently accurate for 
the purpose intended. 

7. temperature; 

During the periods of germination and initial growth the cultures 
were kept in a basement room where the temperature varied between 
23 and 28 degrees C. After the seedlings were well above the surface 
of the soil the covers of the pans were removed and the cultures taken 
to the greenhouse, where the corn was allowed to grow until it was 
from five to six inches tall. It was then taken up and all abnormal 
seedlings were carefully examined. 

III. Experimentation and Discussion 

1. EFFECTS OF THE PERIOD OF IMMERSION AND THE 
MOISTURE CONTENT OF THE SOIL 

As already indicated, the water content of the soil in which the 
grains, after immersion in kerosene, are planted has a very marked 
effect on germination. The data that follow in tables 1 to 4 inclusive 
show the per cent, of germination and normal growth as affected by 
the period of immersion in kerosene and the water content of the soil. 

The kerosene used was a product of the Standard Oil Company, 
on the market under the trade name "Perfection." 

In all tests recorded in the tables, the grains were carefully se- 
lected before immersing them in the kerosene, but no selection was 
made after removing them from the oil. 

The time indicated under the heading "kerosene treatment" gives 
the period during which the grains were immersed in the oil. In the 
column "after treatment" is indicated the treatment of the grains after 
removal from the kerosene and before planting. In every case where 
it is not specifically stated to the contrary, the grains were superficially 
dried with a towel immediately after removing them from the oil. 
When this was not done it is indicated in the table by the word "none." 
The grains in these instances were planted directly from the kerosene. 

A grain was considered germinated if it showed a decided growth 
(1 inch) of radicle or coleoptile. 



251 

Under the heading "No., injured" are recorded the number of 
seedlings showing injuries of one form or another resulting from the 
treatment. 

The variety of corn used in the experiments of Series A, Tables 
i, 2, and 3, was Boone County White; Table 4, Golden Eagle. In all 
other experiments Champion White Pearl was used. The first two 
are dent varieties. The Champion White Pearl has a large, hard, 
smooth grain. Extended comparisons between it and the dent vari- 
eties showed but slight differences in respect to the effects of the kero- 
sene. 



252 



Series A 



Tables i to 4 inclusive. Germination and grozvth as affected by 
the period of immersion in kerosene and the moisture content of soil. 



Table 1. Boone County White Coen in a 30% Saturated Soil 



Trial 


No. of 


Kerosene 


After 


No. 


No. 


Per ct. 


Per ct. 


grains 


treatment 


treatment 


germ. 


in- 
jured 


germ. 


norm. 

growth 


1 


50 


dipped 


3 da. air 


50 





100 


100 




50 


1 min. 


> } 


50 


1 


100 


98 




50 


5 min. 


>} 


50 


1 


100 


98 


Check 


25 






25 


1 


100 


96 


2 


50 


10 min. 


3 da. air 


50 





100 


100 




50 


15 min. 


)> 


50 





100 


100 




50 


30 min. 


>) 


50 


3 


100 


94 


Check 


25 






25 


1 


100 


96 


3 


50 


1 hr. 


3 da. air 


50 


1 


100 


98 




50 


2 hr. 


> > 


50 





100 


100 




50 


3 hr. 


) > 


50 


1 


100 


98 




50 


6 hr. 


>> 


50 


2 


100 


96 




50 


8 hr. 


)} 


50 





100 


100 




50 


14 hr. 


>> 


50 





100 


100 


Check 


50 






50 





100 


100 


4 


50 


1 da. 


3 da. air 


50 





100 


100 




50 


3 da. 


>> 


50 


2 


100 


96 




50 


6 da. 


> 1 


50 





100 


100 


Check 


25 






25 





100 


100 


4a 


100 


1 da. 


5 da. air 


100 


2 


100 


98 




100 


3 da. 


j ? 


100 


1 


100 


99 




100 


6 da. 


j ■> 


100 


2 


100 


98 


Check 


25 






25 





100 


100 


5 


100 


10 da. 


5 da. air 


92 


5 


92 


87 


Check 


25 






25 





100 


100 


6 


100 


25 da. 


5 da. air 


85 


3 


85 


82 


Check 


25 






25 





100 


100 


7 


100 


30 da. 


5 da. air 


86 


10 


86 


76 


Check 


25 






24 





96 


96 


8 


100 


50 da. 


5 da. air 


76 


3 


76 


73 


Cheek 


25 






25 





100 


100 


9 


100 


120 da. 


5 da. air 


72 


5 


72 


67 


Check 


25 






25 





100 


100 


10 


100 


158 da. 


5 da. air 


64 





64 


64 


Check 


25 






25 


1 


100 


96 


11 


100 


190 da. 


5 da. air 


57 





57 


57 


Check 


25 






25 





100 


100 


12 


100 


215 da. 


5 da. air 


60 


2 


60 


58 


Check 


25 






25 





100 


100 


13 


100 


1 yr. 


5 da. air 


66 





66 


66 


Check 


25 






25 


1 


100 


96 


14 


100 


2 yrs. 


5 da. air 


56 





56 


56 



253 



Series A — Continued 
Table 2. Boone County White Corn in a 50% Saturated Soil 



Trial 


No. of 

grains 


Kerosene 
treatment 


After 
treatment 


No. 
germ. 


No. 

in- 
jured 


Per ct. 
germ. 


Per ct. 
norm, 
growth 


1 

Check 


50 
50 
50 
25 


dipped 
1 min. 
5 min. 


3 da. air 


41 

44 
45 
25 


1 
1 

1 



82 

88 

90 

100 


80 

86 

88 

100 


2 

Check 


50 
50 
50 
25 


10 min. 
15 min. 
30 min. 


3 da. air 
>> 


40 
44 

42 
24 



1 
1 
1 


80 
88 
84 
96 


80 
86 
82 
92 


3 

Check 


50 
50 
50 
50 
50 
50 


1 hr. 

2 hr. 

3 hr. 
6 hr. 
8 hr. 


3 da. air 

;> 
> y 
j > 
>} 


43 
40 
38 
36 
38 
49 


2 
2 
2 
1 
1 
1 


86 
80 
76 
72 
76 
98 


82 
76 

72 
70 
74 
96 


4 
Check 


50 
50 
50 

25 


1 da. 
3 da. 
6 da. 


3 da. air 


36 
37 
33 

25 


1 
2 
1 
1 


72 

74 

66 

100 


70 
70 
64 
96 


5 

Check 


100 

25 


10 da. 


5 da. air 


60 
25 


1 




60 
100 


58 
100 


6 

Check 


100 

25 


25 da. 


5 da. air 


61 
25 


8 



61 
100 


53 
100 


7 
Check 


100 
25 


30 da. 


5 da. air 


62 

24 


3 




62 
96 


59 
96 


8 

Check 


100 
25 


50 da. 


5 da. air 


60 
25 


3 



60 
100 


57 
100 


9 

Check 


100 
25 


120 da. 


5 da. air 


56 
24 



1 


56 
96 


56 
92 


10 

Check 


100 
25 


158 da. 


5 da. air 


56 

25 


1 



56 
100 


55 
100 


11 

Check 


100 
25 


190 da. 


5 da. air 


53 
100 






53 
100 


53 
100 


12 

Check 


100 
25 


215 da. 


5 da. air 


47 
23 


2 



47 
92 


45 
92 


13 

Check 


100 
25 


1 yr. 


5 da. air 


48 
25 






48 
100 


48 
100 


14 

Check 


100 
25 


2 yrs. 


5 da. air 


40 
25 






40 
100 


40 
100 



254 



Table 3. 



Series A— 

Boone County White 



-Continued 

Corn in a 75% Saturated Soil 





No. of 


Kerosene 


After 


No. 


No. 


Per ct. 


Per ct. 


Trial 


grains 


treatment 


treatment 


germ. 


in- 

j nred 


germ. 


norm, 
growth 


1 


50 


dipped 


3 da. air 


27 





54 


54 




50 


1 min. 


7 1 


30 


1 


60 


58 




50 


5 min. 


; ) 


26 


1 


52 


50 


Check 


25 






24 


1 


96 


92 


2 


50 


10 min. 


3 da. air 


28 


1 


56 


54 




50 


15 min. 


} > 


33 


1 


66 


64 




50 


30 min. 


> > 


30 





60 


60 


Check 


25 






23 


2 


92 


84 


3 


50 


1 hr. 


3 da. air 


31 





62 


62 




50 


2 hr. 


} > 


28 


2 


56 


52 




50 


3 hr. 


>i 


25 


1 


50 


48 




50 


6 hr. 


> ) 


22 


1 


44 


42 




50 


8 hr. 


> » 


23 





46 


46 




50 


14 hr. 


J 7 


27 


5 


54 


44 


Check 


50 






45 


1 


90 


88 


4 


50 


1 da. 


3 da. air 


25 


2 


50 


46 




50 


3 da. 


; ; 


30 


6 


60 


48 




50 


6 da. 


> } 


22 


2 


44 


40 


Check 


25 






23 


1 


96 


88 


5 


100 


10 da. 


5 da. air 


42 


3 


42 


39 


Check 


25 






24 





96 


96 


6 


100 


25 da. 


5 da. air 


40 


4 


40 


36 


Check 


25 






25 





100 


100 


7 


100 


30 da. 


5 da. air 


41 


2 


41 


39 


Check 


25 






23 





92 


92 


8 


100 


50 da. 


5 da. air 


35 


1 


35 


34 


Check 


25 






25 


1 


100 


96 


9 


100 


120 da. 


5 da. air 


28 


2 


28 


26 


Check 


25 






25 





100 


100 


10 


100 


158 da. 


5 da. air 


22 


2 


22 


20 


Check 


25 






24 





96 


96 


11 


100 


190 da. 


5 da. air 


25 


4 


25 


21 


Check 


25 






23 





92 


92 


12 


100 


215 da. 


5 da. air 


26 


5 


26 


21 


Check 


25 






25 


2 


100 


92 


13 


100 


1 yr. 


5 da. air 


12 


4 


12 


8 


Check 


25 






24 





96 


96 


14 


100 


2 yr. 


5 da. air 


8 


2 


8 


6 


Check 


25 






25 


1 


100 


96 



255 



2. LONG PEEIODS OF IMMERSION 



Reference has already been made to the work started on this 
problem in the laboratory of plant physiology at the University of 
Illinois previous to the publication of the report by Professor Forbes 
('08). This work was abandoned before any definite results had 
been obtained, but the corn immersed in kerosene at that time (Feb- 
ruary 6, 1906) was set aside and kept in the storeroom of the labora- 
tory in a loosely covered fruit- jar until the present work was begun. 
The oil had become yellow and was of the consistency of thin syrup. 
There was about a pint of this corn — an amount far too small to per- 
mit any elaborate tests, but sufficient to demonstrate conclusively that 
under optimum conditions a considerable portion of it was capable of 
germination and perfectly normal growth. 

The majority of the trials recorded in Table 4 were made when 
the preliminary experiments, already referred to, were in progress. 
Of these trials, No. 3 yielded the highest per cent, of germination 
and was in every way the most satisfactory of any which had been 
made up to that time. After the treatment indicated in the table, the 
grains used in this trial were placed on filter-paper in a germinating 
pan with barely enough moisture present to initiate the growth proc- 
esses. As soon as a definite growth of root and coleoptile appeared 
the grains were transferred to soil in which the moisture was some- 
what higher but which did not exceed 30% saturation. This method 
was followed in all subsequent trials made with this corn. The seed- 
lings recorded in the column under per cent, of normal growth were 
just as vigorous and .had just as good color as the check seedlings 
which were grown from corn less than one year old. Plate XVI is a 
picture of two stalks of the corn grown from grains immersed in kero- 
sene for eight years (Trial 9, Table 4). 

A number of attempts were made to germinate grains of this 
corn in 50 and 75% saturated soil but all were complete failures. 



256 

Series A — Concluded 
Table 4. 

Golden Eagle Corn, immersed in kerosene February 6, 1906. Trial 1 was made 
July 11, 1911. The others followed as the time of the kerosene treatment indicates. 
Soil 30% saturated. 



Trial 


No. 

grains 


Kerosene 
treatment 


After- 
treatment 


Per ct. 
germ. 


% Norm, 
growth 


1 


50 


5 yrs, 5 mos., 5 da. 


48 hrs. clay, 12 hrs. air 


40 


40 


2 


50 


5 J 


48 hrs. plaster of Paris, 12 
hrs. air 


44 


44 


3 


100 


5 yrs., 5 mos., 22 da. 


7 da. plaster of Paris, 1 da. 
air, 8 hrs. running water 


64 


55 


4 


35 


•j > 


60 da. plaster of Paris 


65 


56 


5 


35 


)) 


None 


32 


32 


6 


25 


5 yrs., 6 mos., 8 da. 


60 da. plaster of Paris 


58 


50 


7 


25 


}} 


60 da. air 


44 


36 


8 


20 


6 yrs., 2 mos. 


10 da. air 


50 


40 


9 


20 


8 yrs. 


5 min. chloroform, 5 da. air 


20 


15 



3. TYPES OF ABNOBMALITIES 

In soils of 50 and 75% saturation, abnormally swollen grains oc- 
curred frequently. A watery fluid collected inside the membranes in 
considerable quantities. By slight pressure several drops could be se- 
cured from a single grain. Microscopical examination of the ex- 
tracted liquid showed the presence of both perfect and corroded starch 
grains. Occasionally in the 75% saturated soil this liquid seemed to 
undergo fermentation. The pericarp, in these instances, was ruptured 
and the accumulated liquid made its way to the surface of the soil 
where it spread out and, drying, formed a hard white crust. Exami- 
nation of this crust under the microscope showed corroded starch 
grains and a large number of bacteria. The bacteria were of uniform 
shape and size and apparently belonged to a single species. Swellings 
as above described occurred among the grains which had failed to 
germinate and among those which were growing normally. They 
were also occasionally found among the normal grains used as a check, 
but much less frequently than among the treated grains. From the 
observations made, there was nothing to indicate that the swollen con- 
dition had any bearing on the germination or growth of the corn. 



257 

When punctured by a pin-prick the liquid inside the grain oozed out 
and no further accumulation of it occurred. This showed that it prob- 
ably was due to the high osmotic pressure inside the intact membranes 
and to an abundance of available water in the surrounding soil. No 
swollen grains appeared in cultures in which the moisture content of 
the soil was but 30% of saturation or less. 

One of the most noticeable injuries, though by no means the most 
frequent, was a curled and twisted condition of the leaves due to their 
inability to unfold normally in the process of growth. An examination 
of the tips of these leaves showed, in the majority of cases, that they 
were dead and that they adhered to each other on that account. It 
was possible to produce typical cases of the injury on control seedlings 
by touching the tip of the growing shoot immediately after it appeared 
through the coleoptile with an injurious reagent. Of the reagents 
used for this purpose sulphuric acid was the most certain to cause the 
abnormal growth. Kerosene applied in the same manner produced the 
injury, but it was by no means as effective as the sulphuric acid. The 
injury appeared occasionally among control seedlings, but there can 
be no doubt that the unusual frequency of the deformity in treated 
grains was due to the effects of the kerosene. 

Another abnormality attributable to the kerosene was a much 
enlarged and thickened coleoptile which the growing plumule occa- 
sionally failed to rupture. Whenever this unusual development ap- 
peared it was observed that the plumule had not grown nearly as far in 
the coleoptile as it ordinarily does. In some instances the plumule failed 
to develop, leaving the coleoptile entirely empty. This seemed to in- 
dicate that the coleoptile is less sensitive to the kerosene than the en- 
closed structures are, and that the enlargement is correlated with the 
failure of the plumule to develop. 

The most frequent injury was the death of the shoot. This oc- 
curred many times in grains from which the root grew normally. 
Very rarely in these experiments did the shoot grow when the root 
had been killed. 

The injuries mentioned above were not as distinct from each 
other as the descriptions might seem to indicate. As a matter of fact 
there was an imperceptible gradation from one to another. The de- 
formed leaves seem to represent the first visible injurious effects of the 
kerosene treatment. Increasing ill effects, due to an increase in the 
period of immersion, could be followed through a gradually decreasing 
vitality, to death. The action of the kerosene in producing injuries, 
and other evidences to be presented later, indicate that kerosene is not 
a violent poison to the growing corn-seedling. 



258 



4. DEY MEMBEANES 



It is evident that the kerosene did not act uniformly on the grains 
of corn which were subjected to the treatment. Some were killed, 
some injured, while others showed no injurious effects whatsoever. 
These conditions prevailed regardless of the period of immersion. No 
length of treatment was found which directly killed or even injured 
all the grains. This fact becomes significant when it is noted that the 
kerosene treatment was varied from a mere dipping to continuous im- 
mersion for a period of eight years. 

Rather early in my work it was suspected that the oil penetrated 
the membranes of some grains more readily than those of others. 
Some embryos had an oil-soaked appearance after the kerosene treat- 
ment while others seemed free from the oil. 

To obtain further evidence of the permeability of the coats to 
the oil, 200 grains of Champion White Pearl were placed in kerosene 
colored with Sudan III. After 50 days' immersion the corn was re- 
moved and superficially dried with a towel. One hundred of these 
grains, taken at random, were cut transversely through the middle of 
the embryos and carefully examined for the presence of colored oil. 
Seventy-eight showed no trace of oil or color in the embryos; five 
were slightly stained; the remaining seventeen were deeply stained 
and showed the presence of oil in considerable quantities. In no case 
was there any evidence of oil in the endosperm. The remaining 100 
grains treated with Sudan III kerosene, as above indicated, were left 
exposed to the air for twelve hours and then planted in a 30% satu- 
rated soil. In cutting through the 100 grains taken at random from 
the 200 treated, it very soon became apparent that in most cases a 
selection from external appearances alone could be made. This was 
attempted before planting the remaining 100 of the treated grains. 
From external examination these 100 grains were divided into three 
groups : first, those seeming to be free from the colored oil ; second, 
those showing slight traces of it; and third, those in which the em- 
bryos were deeply stained. The grains of these groups were planted 
in separate rows in the culture pans and were kept under identical con- 
ditions. Of the 76 grains of group one, all germinated and produced 
normal seedlings. Nine out of 14 of the second group, germinated 
but produced seedlings showing greater or less injury. One grain 
from group three germinated, the seedling being decidedly weak. 

It has already been stated that the grains were carefully selected 
before they were immersed in the oil. Any having visible defects 
were rejected, but no selection was made after removing the corn from 
the oil,- with the following exception : April 20, a quantity of the 



259 

Champion White Pearl was removed from the kerosene in which it 
had been placed February 6 — 76 days' immersion — and 50 grains were 
selected from it which seemed from external appearances to be free 
from kerosene. These grains were exposed to the air for ten days 
and then planted in a 30% saturated soil. Forty-nine, or 98% of 
them, developed normal seedlings. From these results it is apparent 
that an almost perfect germination can be secured by selecting grains 
showing no traces of stain in the embryos. The selection of grains 
with membranes slightly permeable to the colored oil can by no means 
so easily be made. The structures at the tips of the grains always take 
up the oil readily and it spreads for some distance from them, giving 
the appearance of stain within the embryos when in reality it is en- 
tirely superficial. The absence of Sudan III in the grain does not 
necessarily mean the absence of kerosene, since the membranes may 
be semi-permeable. A number of experiments were undertaken to 
test this assumption. 

Grains immersed in Sudan III kerosene for long periods and free 
from stain were carefully dissected, and the structures within the 
coats were tested by the picric acid methods of Schulz ('08), and 
Krauz ('09). The results were uniformly negative. It was found 
that tests by these reagents were not nearly so delicate as the sense 
of taste. In no case, however, could the presence of kerosene be de- 
tected in unstained grains. On the other hand, it could be readily de- 
tected in grains which had been but slightly stained with Sudan III. 
It should be here stated that the above holds true only for air-dry 
grains. 

These facts indicate very clearly that the kerosene enters some 
of the grains and is excluded from others. Whether the membranes 
of the grains showing penetration had been mechanically injured or 
were of different physical structure has not been determined. In 
either case the result would be the same. Undoubtedly there are many 
opportunities for mechanical injuries, but the fact that the number 
of grains exhibiting a penetration of the kerosene increases with the 
time of immersion would indicate that the membranes are not uni- 
formly impermeable. 

Membranes of widely different properties are not uncommon in 
seeds of the same kind. Many cases of delayed germination are at- 
tributed to this peculiarity [see Crocker ('06) ; Hanlein ('8o) ; Nobbe 
and Hanlein ('77)]. It is not unlikely that the membranes of the corn 
kernel are sufficiently different in their organization or development to 
permit a rather wide variation in their permeability to kerosene. 

A number of interesting studies on the physical properties of 
plant membranes have appeared recently. Brown ('07 and '09) found 



260 



the "seed" of Hordeum vulgare to be enclosed in a semi-permeable 
membrane. He found the aleurone layer of Hordeum vulgare to con- 
tain a pigment which serves as an indicator for acids and alkalis. This 
was not only a very interesting discovery but one which materially 
aided in the successful conduct of his work. He learned that the in- 
tact membranes of H. vulgare are impermeable to sulphuric acid; con- 
sequently when, in the presence of this acid, the purple pigment 
changed to a pink color it indicated imperfect membranes. Thus it 
was possible for him to select "seed" with intact membranes for ex- 
perimental purposes. From all indications, Sudan III is just as ef- 
ficient for determining imperfections in the membranes of Zea as are 
the color reactions described by Brown. 

Schroder ('n), using Brown's methods, found the same kind 
of semi-permeable membranes in wheat. More recently Shull ('13), 
has made similar studies on the tests of Xanthium glabratum and 
demonstrated selective semi-permeability like that found in Hordeum. 

5. MUTILATED MEMBEANES 

To determine the toxic action of kerosene on the embryo, the 
outer membranes were punctured at several places and also removed. 
The following tables (Series B, tables 5 to 10 inclusive) give the re- 
sults. 

Series B 

Tables 5 to 10 inclusive. Effects of kerosene on grains with mem- 
branes punctured before immersion. Champion White Pearl Corn 
germinated in a 25% saturated soil. 







Table 5. 


Normal Grains (Control) 






Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


fc Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


50 





100 


100 


2 


50 


10 days 


;; 


50 





100 


100 


3 


50 


15 days 


>) 


50 


2 


100 


96 


4 


50 


20 days 


n 


50 


2 


100 


96 


5 


50 


25 days 


}} 


46 


3 


92 


86 


6 


50 


35 days 


}> 


44 


6 


88 


76 


7 


50 


50 days 


)> 


40 


4 


80 


72 


8 


50 


75 days 


}) 


38 


1 


76 


74 



Table 6. Pedicle Eemoved 





No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


% Norm. 


Trial 


grains 


treatment 


treatment 
3 da. air 


germ. 


j ured 


germ. 


growth 


1 


50 


5 days 


50 





100 


100 


2 


50 


10 days 


) > 


50 





100 


100 


3 


50 


15 days 


n 


50 





100 


100 


4. 


50 


20 days 


; 1 


50 


1 


100 


98 


5 


50 


25 days 


.*> 


50 





100 


100 


6 


50 


35 days 


;> 


50 





100 


96 


7 


50 


50 days 


' ■' 


50 


1 


100 


98 


8 


50 


75 days 


t) 


47 




94 


94 



261 
Series B — Concluded 

Table 7. Pericarp Punctured at Distal End of Coleoptile 



Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per et. 


% Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


50 


30 


300 


40* 


o 


50 


10 days 


>> 


44 


38 


88 


32 


3 


50 


15 days 


ft 


34 


32 


68 


04t 


4 


50 


20 days 


S 1 


30 


28 


60 


04 1 


5 


50 


25 days 


j? 


22 


22 


44 


00 


6 


50 


35 days 


> } 


6 


5 


12 


02 


7 


50 


50 days 


it 







00 


00 


8 


50 


75 days 


)) 


1 


1 


02 


00 



*Not so vigorous as control. 
tRetarded and decidedly weak. 

Table 8. Membranes Lying within the Pedicle Punctured 



Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


% Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


50 





100 


100* 


2 


50 


10 days 


}} 


50 





100 


100* 


3 


50 


15 days 


> i 


48 


40 


96 


16t 


4 


50 


20 days 


; J 


50 


42 


100 


16 1 


5 


50 


25 days 


>i 


32 


32 


64 


00 


6 


50 


35 days 


17 


30 


28 


60 


04 


7 


50 


50 days 


it 


20 


20 


40 


00 


8 


50 


75 days 


it 







00 


00 



*Slightly retarded. 
tRetarded and weak. 



Table 9. Pericarp Eemoved 



Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


%Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


50 


12 


100 


76* 


2 


50 


10 days 


it 


50 


10 


100 


80* 


3 


50 


15 days 


)) 


36 


20 


72 


32* 


4 


50 


20 days 


1 7 


30 


30 


60 


00 


5 


50 


25 days 


7) 


16 


16 


32 


00 


6 


50 


35 days 


i ; 


10 


10 


20 


00 


7 


50 


50 days 


17 


2 


2 


04 


00 


8 


50 


75 days 


if 







00 


00 



♦Retarded and weaker than control. 



Table 10. Pericarp Eemoved 



Trial 


No. of 




grains 


1 


50 


2 


50 


3 


50 


4 


50 


5 


50 


6 


50 


7 


50 


8 


50 



Exposed to dry air 



5 days 
10 days 
15 days 
20 days 
25 days 
35 days 
50 days 
75 days 



No. 


No. in- 


Per ct. 


%Norm. 


germ. 


jured 


germ. 


growth 


50 


5 


100 


90 


48 


7 


96 


82 


46 


?* 


92 


?* 


45 


?* 


90 


?* 


46 


?* 


92 


?* 


40 


?* 


80 


?* 


48 


?* 


96 


?* 


46 


?* 


92 


?* 



*These seedlings were uniformly weak. It could not be told at the time of observa tion whether 
they would recover or not. 



262 

The fact that the pericarp is greatly modified at the tip of the 
grain — the pedicle — into a very porous vascular tissue, introduces a 
factor that greatly increases the difficulty in a study of the mem- 
branes. At this point, however, the pericarp is reinforced within by a 
compact remnant of the nucellus which, when perfect, effectively pre- 
vents the oil from penetrating the grains. There can be no question but 
that this is the usual point of ingress into those grains in which the 
embryos are stained. The colored oil invariably makes its appearance 
here and gradually passes up through the embryo. That the pedicle 
itself is not only valueless for excluding the oil but that it is the source 
of positive injury is shown in Table 6. The pedicles were carefully 
broken off from these grains before immersing them in kerosene, and it 
was found that a higher rate of germination resulted from grains so 
treated. It is altogether likely that the spongy tissue of the pedicle, by 
retaining rather large quantities of the kerosene, is responsible for a 
decrease in germination when it is not removed. The oil remaining 
in or on the grains seems to be absorbed and carried to the regions 
of growth as soon as the growth processes are initiated. If the 
amount is beyond a certain limit, injury is produced. 

The -effects of removing the pedicle and slightly puncturing the 
membranes within it are shown in Table 8. The best place to puncture 
the pericarp without injuring the embryo is near the distal end of the 
coleoptile where, in the process of maturing, a small wrinkle is formed 
in a rather large proportion of the grains. The membranes at this 
point can readily be ruptured with a needle without the slightest in- 
jury to the underlying parts. 

The effects of thus puncturing the coats (Table j) are in a gen- 
eral way comparable to those secured by puncturing the membranes 
lying within the pedicle. In the latter case, however, the grains did 
not show the injurious effects as quickly as in the former. In both 
cases the colored oil penetrated the embryos in sufficient quantities to 
be plainly visible in twenty-four hours. It is important to note that, 
excepting a slight retardation, ioo% of the grains in Table 8 con- 
tinued to produce normal seedlings after immersion in kerosene for a 
period of ten days. This shows that the presence of a limited amount 
of oil in the embryo is not necessarily injurious. 

By soaking the grains in tepid water for ten minutes the entire 
pericarp, including the pedicle, is very easily removed without in- 
jury to the parts within. After thus removing it, the grains were 
dried at room temperature for five days and then immersed in kero- 
sene. The results (Table 9) correspond closely to those obtained in 
the experiments with punctured membranes and show that a punctured 



263 



^•■'V'.V 
I 



>■■.. ■::,■■■::*,'■:■■£.■- 




pericarp is -equivalent to its removal. In either case the dormant 
grains are killed within a comparatively short time (75 days). 

It will be noticed that grains with the pericarp removed but not 
otherwise treated (Table 10) retained the power of germination to 
a fairly high degree for the time indicated in the table ; but such grains 
after ten days' exposure to the dry air of a steam- 
heated room produced seedlings that were uni- 
formly weak. This indicates that these mem- 
branes play a very important role in preserving 
the vitality of the grains. 

The dry pericarp, not including the pedicle, 
was shown to be impermeable to kerosene in an- 
other way. A large grain of the Champion White 
Pearl furnishes a membrane fully one-half inch 
in diameter. It is easily removed after soaking 
the grain for a few minutes in warm water. 
After drying, it can be cemented over the end of 
a glass tube for use either as a barometer or as 
an osmometer. This simple piece of apparatus 
was, as far as I know, first devised by Becquerel 
('07) in his studies on the permeability of seed 
coats to certain gases. Shull ('13) also used it 
with success in demonstrating the semi-permea- 
bility of the testa of Xanthium. Adapted for my 
work, the apparatus was constructed as shown in 
the accompanying sketch. 
Considerable difficulty was experienced in finding a cement not 
soluble in kerosene. Sealing-wax, such as is used by express com- 
panies for sealing valuable packages, was finally found to serve the 
purpose admirably. The rubber stopper at the end of the glass cylin- 
der serves as a foundation to which the membrane is cemented. The 
small glass tube (Fig. 1, cc) was allowed to protrude three or four 
millimeters through the perforated rubber stopper. A layer of wax 
equal in thickness to th-e protruding portion of the tube was then ap- 
plied and the edges of the membrane were pressed into it while it was 
still soft. More wax was then applied to make the seal perfect. The 
central portion of the membrane over the end of the small glass tube 
was left entirely free from wax. 

Such an apparatus was set up March 7, with kerosene on one side 
of the membrane and with plaster of Paris as an absorbent on the 
other. At the present time (May 6) the wax is holding perfectly and 
there has been no trace of oil passed through the membrane. A 



Fig. 1. Apparatus used 
in testing directly the per- 
meability of the pericarp 
of Zea: a, membrane; bb, 
rubber stopper; cc, glass 
tube; d, receptacle for 
liquid to be tested. 



264 

similar apparatus was set up as a barometer November 29 and has 
supported a mercury column representing a complete atmospheric pres- 
sure since that time (5 mos., 7 days). The mercury rises and falls 
with the changes in atmospheric conditions, but no fall attributable 
to the penetration of air through the membrane has taken place. 

No effort has been made to extend these studies beyond the limits 
indicated in the title of the paper, but as a matter of interest the ap- 
paratus was set up as an osmometer with a saturated solution of 
sodium chloride on the inside of the membrane and distilled water on 
the outside. The contents of the upper tube, a cross-section of which 
had the same area as the exposed membrane, rose at the rate of 4^ 
cm. a day for four days. Before the rise had ceased the liquid out- 
side the membrane was tested with silver nitrate for the presence of 
sodium chlorid'e. The test showed the presence of the salt in large 
quantities. 

From these experiments it may be concluded that under the con- 
ditions described the membrane is impermeable to kerosene and to 
atmospheric gases, but that it is permeable to sodium chloride. 



6. MOISTUEE CONTENT OF THE GRAINS 

The data thus far discussed pertain to the corn which was 
thoroughly air-dried before it was immersed in kerosene. The fol- 
lowing experiments show the effects of similar treatments on grains 
containing different amounts of moisture at the time of immersion. 

Series C 

Tables 11 to 14 inclusive. The effects of different amounts of 
water in the grains at time of immersion in kerosene. Champion 
White Pearl Com germinated in a 25% saturated soil. 

Table 11. Water in Grains Desiccated to Constant Weight at 100° C. 



Samples 
(50 grains) 


Original 
weight 


Dry 

weight 


Ratio of water 
to dry weight 


Old corn 


24.040 
26.832 
28.185 


23.523 
22.112 

22.468 


2.19% 
21.30% 
25.44% 


New corn 


New corn soaked 1 hr 



Table 12. Old Corn. Water Content Equivalent to 2.19 per cent, of Dry Weight 



Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


% Norm. 




grams 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


50 





100 


100 


2 


50 ■ 


10 days 


} ) 


50 





100 


100 


3 


50 


15 days 


; ! 


48 


4 


96 


88 


4 


50 


20 days 


1 > 


46 





92 


88 



265 



Series C — Concluded 
Table 13. New Corn. Water Content Equivalent to 21.3 per cent, of Dry Weight 



Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


% Norm. 


grams 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


46 


4 


92 


84 


2 


50 


10 days 


> > 


36 


8 


72 


56 


3 


50 


15 days 


; ? 


8 


8 


16 


00 


4 


50 


20 days 


; ? 







00 


00 



Table 14. 



New Corn Soaked in Water 1 hr. Water Content Equivalent to 
25.44 per cent, of Dry Weight 



Trial 


No. of 
grains 


Kerosene 
treatment 


After 
treatment 


No. 
germ. 


No. in- 
jured 


Per ct. 
germ. 


% Norm, 
growth 


1 

2 
3 


50 
50 
50 


5 days 
10 days 
15 days 


3 da. air 


42 

10 




1 

5 



84 
20 
00 


82 
10 
00 



The amount of water contained in the respective samples used, 
as shown by desiccation to constant weight at ioo degrees C, is re- 
corded in Table n. The old corn was harvested one year previous 
and had been stored in the dry rooms of the laboratory for approxi- 
mately six months. The new corn had just been harvested, but was 
fully mature and sound in every way. It will be noted that the old 
corn contained an amount of water equivalent to 2.19% of the con- 
stant weight at 100 degrees C. ; the new corn, 21.3%; and the new 
corn soaked in water for one hour, 25.44%. Under normal condi- 
tions both the old corn and the new corn germinated perfectly. 

The corn containing water in the amounts indicated above was 
immersed in kerosene and tested for viability at intervals of five days. 
The results are brought together in tables 12, 13, and 14. A glance at 
these tables shows that after a period of more than five daA^s' immer- 
sion in kerosene the injuries are very decidedly increased in the grains 
of high water content. One hundred per cent, of the dry grains germi- 
nated after ten days' immersion in kerosene, while the germination of 
the new corn and the new corn soaked in water dropped to 36 and 10% 
respectively. Immersion in kerosene for twenty days proved fatal 
to all the corn of each lot containing the higher percentages of water. 
The air-dry corn, after an equal period of immersion, gave 92% 
germination and 88% normal growth. 

Since the per cent, of germination falls so rapidly in corn not fully 
dry and in corn soaked in water for a short time, it seems evident that 
some physical change of the investing membranes takes place on 
moistening, and that they become more readily permeable to kerosene. 



266 

After twenty days' immersion in Sudan III kerosene, and after 
germination tests had proven all the grains dead, the remaining grains 
of the new corn were carefully examined to determine the number 
showing penetration of the stain. Of the 161 grains, 24, or approxi- 
mately 15%, were stained. Twenty-four days later — 74 days' immer- 
sion — the number had increased to 45, or 25%. If one should attempt 
to judge the viability of the grains by the presence or absence of the 
stain, as was done so effectively in the dry grains, the rate of germina- 
tion should be approximately 75%. Both stained and unstained 
grains, however, had lost all power of germination and the presence 
of kerosene was easify demonstrated in both. The conclusion nat- 
urally follows that the membranes of the moist grains permit the 
penetration of the kerosene, but that they effectively prevent the pas- 
sage of the Sudan III. The percentage of grains stained by Sudan III 
was approximately the same as in the dry grains. This supports the 
view previously expressed; namely, that the stained embryo is an in- 
dication of imperfect membranes. 

7. VARIATIONS IN SOIL MOISTURE 

That some grains of corn bear immersion for a period of eight 
years in kerosene is experimentally proven. This, however, is not true 
of all grains of like origin subjected to similar treatment. In every 
sample taken at random a certain percentage of the grains fail to 
germinate after a comparatively short period of immersion. By means 
of the Sudan III it has been conclusively established that a limited 
number of grains of a random sample are stained and that these even- 
tually fail to germinate even under the most favorable conditions. 
Death in these instances is due to the toxic action of the kerosene on 
the dormant embryo. Since it has been shown that the dry mem- 
branes are impermeable or only slightly permeable to kerosene, the 
presence of the oil within the membranes, in sufficient quantities to 
cause death, is attributable to imperfect membranes. The presence of 
small quantities of kerosene within the grain, however, does not neces- 
sarily prove injurious. Grains immersed in kerosene for the same 
periods of time give very unlike results when placed under different 
conditions for germination. It was found that in the presence of 
abundant moisture the injurious effects of the kerosene treatment are 
especially marked. In the experiments (Series A) in which grains, 
similarly treated with kerosene, were placed in soils with different 
moisture content, this injury was clearly brought out. When the 
amount of water in the soil was reduced from 30% saturation (Series 
A, Table 1) to 25% saturation (Series B, Table 5) the per cent, of 



267 

germination was increased and the growth of the seedlings was more 
nearly normal; but when the water content of the soil was increased to 
50 or 75% of saturation (Series A, Tables 2 and 3) the per cent, of 
germination was markedly decreased and the subsequent growth of 
many of the seedlings abnormal. 

The germination and growth of grains immersed in Sudan III 
kerosene but unstained is normal in 25 and 30% saturated soils. The 
slightly stained grains, that is those containing small quantities of 
kerosene, frequently produced normal seedlings when the water con- 
tent of the soil did not exceed 25% saturation. In 30% saturated 
soil the per cent, of normal growth of these seedlings was greatly re- 
duced. In soils of 50 and 75% saturation all grains showing the 
slightest penetration were killed, as were also a considerable number 
in which the presence of oil could not be detected from external ex- 
amination. 

Traces of kerosene are always present when once the grains have 
been immersed in it. This is shown by the decreased germination in 
soils of high water content and also by other and more direct evi- 
dences. Grains immersed for comparatively short periods retain the 
taste of the oil after six months' exposure to dry air at room tempera- 
ture. Because of the varying moisture content of the corn, and possibly 
changes due to the presence of the kerosene, the exact amount of oil 
taken up and retained could not be accurately determined. Quantita- 
tive evidence, though desirable, was not necessary to show that a con- 
siderable residue remained after volatilization had been carried to the 
limit used in this work. The question, then, of the disposition of the 
oil or its residues in those cases in which no injurious effects are pro- 
duced becomes important. 

Schmidt ('91), in his studies on the translocation of oils in the 
living plant, devised a method by which he succeeded in directly intro- 
ducing almond oil, cocoa butter, and other oils into the tissues of the 
stem. He showed that these oils were taken up and moved with con- 
siderable rapidity through both stem and leaf. He concluded that both 
neutral oils and fatty acids could be taken up by the growing plant, 
saponified and emulsified in a manner similar to that carried on in the 
animal organism. 

Kryz ('09 and '13), investigating the effects on plants of oils 
used as insecticides, treated Impatiens with vaseline, and Datura and 
Alisma with kerosene. In the latter case he planted the seeds in 
flower-pots containing garden soil and sprinkled the soil with a 5% 
solution of the oil both before germination and after the plants 
had reached considerable size. He showed that the oil was taken up 



268 

and carried through the vascular tissues to the leaves, where it was 
stored in quantities sufficiently large to make its presence easily deter- 
minable. Unfortunately Kryz continued the treatment until the plants 
were killed. He seems not to* have paid any attention to the power 
of recovery of the plant from injuries not at once fatal. 

These investigations led me to believe that under favorable con- 
ditions a limited amount of kerosene might be absorbed and disposed 
of, without injury, by the growing corn seedling. Observations con- 
firmed this belief. The coleoptiles of seedlings grown from grains 
immersed in colored oil frequently showed the red stain. In soils of 
low moisture content these seedlings developed normally, while in soils 
of high moisture content they were either killed or showed pronounced 
injury. Numerous attempts were made to demonstrate the presence 
of the oil in the tissues. Sections were treated with Sudan IlT, 
alkannin, and picric acid benzol (5), but because of the large amount 
of oil normally present in the structures of the young corn seedling 
and the very small amount of kerosene which ordinarily is present, 
the results were not successful. No satisfactory test for demonstrat- 
ing the presence of kerosene in very small quantities has been found. 

The experiments of Kryz were repeated in a modified form and 
his results confirmed. Corn seedlings were grown on filter-paper so 
that the roots penetrated the paper and entered soil contained in a pot 
below. When the seedlings were about three inches tall, from 1 to 3 
drops of Sudan III kerosene were applied to the old grains at the base 
of the seedlings. A drop was equal to one-fiftieth cubic centimeter. 
In a few minutes the stain showed prominently in the stems of the 
seedlings and eventually reached the leaves in quantities sufficiently 
large to be plainly visible to the naked eye. All the seedlings treated 
with three drops died within five days after the treatment. The 
majority of the seedlings treated with one and two drops recovered. 
The amount of oil disposed of was certainly many times as much as 
could be retained in the dry grains immersed in oil and afterwards 
treated to eliminate it. It is apparent that the older seedlings can dis- 
pose of a much greater amount of oil than the younger ones. 

It is evident that within certain limits the seedlings are not in- 
jured by the oil present at the time of planting provided growth is 
initiated in the presence of a minimum amount of water. The small 
quantities of kerosene are toxic in proportion to the increase of the 
moisture content of the soil. In the 50 and 75% saturated soils the 
dormant period of the grain is always less than 36 hours, while in a 
25% saturation the time is extended to approximately five days. This 
increase of time affords the seedling an opportunity to dispose of the 
oils much more slowly, and it does so without injurious effects. 



269 



8. OTHER OILS 



In addition to the kerosene the effects of a number of other 
petroleum oils have been studied. At the present time only the in- 
itial results have been obtained. These results indicate that the in- 
juries due to the penetration of the dormant grains by the oils are 
'essentially the same as in the case of kerosene. The effects on the 
germinating grains, however, differ very widely. The more volatile 
oil (gasoline, Table 16) produces no more injury than does the kero- 
sene. From present indications it seems probable that a high moisture 
content of the soil affects the grains immersed in the more volatile oils 
less than those immersed in kerosene. On the other hand, the injuri- 
ous effects of the heavier oils on germinating grains in soils of either 
low or high moisture content are much more pronounced. The same 
means were employed for eliminating these oils from the grains after 
immersion as were used with the kerosene; viz., wiping the grains 
carefully with a towel and then exposing them to the air. The heavier 
oils do not volatilize as completely as the kerosene and gasoline do. 
The residues dry on the grains, producing a hard coating which pre- 
vents normal germination. 

At present the trend of evidence tends to show that the grains 
bear immersion in the lighter oils without injury for much longer peri- 
ods than in the heavier oils, and that the injurious after-effects of the 
latter are more pronounced than those of the former. 



SERIES D 

Tables 15 to 20 inclusive. Comparisons between kerosene and 
other petroleum oils. Champion White Pearl Corn germinated in a 
25% saturated soil. 

Table 15. Kerosene (Control) 



Trial 


No. of 


Kerosene 


After 


No. 


No. in- 


Per ct. 


Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


50 





100 


100 


2 


50 


10 days 


; j 


50 


3 


100 


94 


3 


50 


15 days 


7 J 


47 


3 


94 


88 


4 


50 


20 days 


; 5 


47 


4 


94 


86 


5 


50 


25 days 


?> 


45 


1 


90 


88 


6 


50 


35 days 


' ' 


43 


1 


86 


82 


7 


50 


50 days 


7 > 


39 


2 


78 


74 


8 


50 


75 days 




34 


1 


68 


66 



Table 16. Gasoline 



Trial 


No. of 


Gasoline 


After 


No. 


No. in- 


Per ct. 


% Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


49 


1 


98 


96 


2 


50 


10 days 


} } 


49 


3 


98 


92 


3 


50 


15 days 


>t 


47 


2 


94 


90 


4 


50 


20 days 


7 7 


47 


3 


94 


88 


5 


50 


25 days 


>t 


45 


1 


90 


88 


6 


50 


35 days 


7 > 


42 


1 


84 


82 


7 


50 


50 days 


)> 


40 





80 


80 


8 


50 


75 days 


7 7 


37 


1 


74 


72 



270 



Series D — Concluded 

Table 17. Kansas Crude Oil 





JNo. of 


Oil 


After 


JNo. 


No. in- 


Per ct. 


% Norm. 


Trial 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


46 


2 


92 


88 


2 


50 


10 days 


>> 


48 


2 


96 


92 


3 


50 


15 days 


it 


50 


6 


100 


88 


4 


50 


20 days 


it 


47 


3 


94 


88 


5 


50 


25 days 


>i 


43 


4 


86 


78 


6 


50 


35 days 


it 


44 


5 


88 


78 


7 


50 


50 days 


>j 


50 


20 


100 


60 


8 


50 


75 days 


t> 


40 


10 


80 


60 



Table 18. Heavy Eed Oil 





No. of 


Oil 


After 


JNo. 


No. in- 


Per ct. 


%Norm. 


Trial 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


-> 


50 


5 days 


3 da. air 


50 





100 


100* 


2 


50 


10 days 


)) 


46 





92 


92* 


3 


50 


15 days 


!) 


40 


5 


80 


70* 


4 


50 


20 days 


ft 


40 


4 


88 


76* 


5 


50 


25 days 




40 


«J 


80 


74* 


6 


50 


35 days 


It 


48 


4 


96 


88* 


7 


50 


50 days 


} ; 


40 


28 


80 


24* 


8 


50 


75 days 


it 


24 


10 


48 


28* 



*A11 seedling's decidedly retarded. 



Table 19. Fuel Oil 





No. of 


Oil 


After 


No. 


No. in- 


Per ct. 


% Norm. 


Trial 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


48 


2 


96 


92* 


2 


50 


10 days 




46 


14 


92 


64* 


3 


50 


15 days 




46 


18 


92 


56* 


4 


50 


20 days 




42 


15 


84 


54* 


5 


50 


25 days 




44 


14 


88 


60* 


6 


50 


35 days 




48 


b 


96 


80* 


7 


50 


50 days 




42 


26 


84 


32* 


8 


50 


75 days 




40 


20 


80 


40* 



*From 2 to 3 days retarded. 



Table 20. Engine Oil 



Trial 


No. of 


Oil 


After 


No. 


No. in- 


Per ct. 


%Norm. 


grains 


treatment 


treatment 


germ. 


jured 


germ. 


growth 


1 


50 


5 days 


3 da. air 


48 


2 


96 


92* 


2 


50 


10 days 




48 


20 


96 


56* 


3 


50 


15 days 




48 


18 


96 


60* 


4 


50 


20 days 




45 


16 


90 


58* 


5 


50 


25 days 




43 


15 


86 


56* 


6 


50 


35 days 




40 


12 


80 


56* 


7 


50 


50 days 




44 


32 


88 


24* 


8 


50 


75 days 


>> 


40 


24 


80 


32* 



♦Retarded 3 days and very uneven. 



271 



9. SUMMAEY OF CONCLUSIONS 



Grains of Zea mais may be immersed in kerosene for periods of 
ten to twenty days without injury if the optimum conditions for the 
germination and growth of such grains are provided. These condi- 
tions include the removal of the superficial oil from the grains and the 
presence of a minimum amount of water during germination and in- 
itial growth. 

Injuries which occur to the dry grains immersed in kerosene for 
longer periods than above indicated are due to the penetration of the 
oil into the embryos through imperfect membranes. 

The dry membranes covering the corn embryo, when perfect, are 
impermeable to kerosene and to Sudan III. 

Some grains of Zea mais may be immersed in kerosene for eight 
years without injury to the dormant embryo. 

The life of dormant grains, with membranes which have been 
mechanically injured, is destroyed within seventy-five days after im- 
mersion in kerosene. 

Kerosene is injurious to the germinating grains in direct propor- 
tion to the length of time of immersion and to the increase of the- 
water content of the soil above the minimum required for germina- 
tion. 

When moist grains are immersed in a solution of kerosene and 
Sudan III, the membranes are penetrated by the kerosene but not by 
the Sudan III. The membranes are, therefore, semi-permeable. 

The germinating corn grain may absorb and dispose of a limited 
amount of kerosene without injury. The smaller the amount of water 
present during germination the larger the quantity of kerosene which 
can be disposed of. Older corn seedlings may dispose of compara- 
tively large quantities of kerosene without injury. 

It is not advisable to treat seed corn with kerosene unless the 
water content of the soil is under control. 

The injurious effects of petroleum oils on germinating corn seem 
to vary inversely as the volatility of the respective oils. 



272 
BIBLIOGRAPHY 



Becquerel, Paul. 

'07. Recherches sur la Vie Latente des Graines. Ann. Sci. Nat., 
Bot, 9 e ser., 5 : 193. 

Brown, Adrian J. 

'07. On the Existence of a Semi -permeable Membrane enclosing 

the Seeds of some of the Gramineae. Ann. Bot., 21 : 79. 
'09. The Selective Permeability of the Coverings of the Seeds of 

Hordeum vulgare. Proc. Roy. Soc. London, Ser. B, 81 : 82. 

Crocker, William. 

'06. Role of Seed Coats in Delayed Germination. Bot. Gaz., 
42 : 265. 

Duggar, B. M., and McCool, M. M. 

'09. Suggestions concerning Treatment of Seed Corn with De- 
terrents against Crows. Circular No. 6, Cornell Agr. Exper. 
Station. 

Forbes, S. A. 

'08. Experiments with Repellents against the Corn Root-aphis, 
1905 and 1906. Bull. No. 130, 111. Agr. Exper. Station. 

Hanlein, H. 

'80. Ueber die Keimkraft von Unkrautsamen. Landw. Ver- 
suchs-Stat, 25 : 465. 

Krauz, Cyrill. 

'09. Beitrag zur Schulzschen Farbenreaktion der Mineralole. 

Chem. Zeit., 33 : 409. 

• 

Kryz, Ferdinand. 

'09. Uber den Einfluss von Erdol auf die Entwicklung von 

Datura und Alisma. Zeit. f. Pflanzenkrank., 19: 449. 
'13. liber die Aufnahme von Vaselinol durch Balsaminen. Zeit. 
f. Pflanzenkrank., 23 : 34. 

Lummis, G. M. 

'03. Effect of Coal Tar, Coal Oil, Gasoline, Benzine and Kero- 
sene on Germination of Maize. Proc. 24th Ann. Meeting Soc. 
Promotion Agr. Sci., p. 96. 



273 

Nobbe, F., und Haenlein, H. 

'yy. Ueber die Resistenz von Samen gegen die ausseren Factoren 
der Keimung. Landw. Versuchs-Stat., 25: 71. 

Schmidt, R. H. 

'91. Ueber Aufnahme und Verarbeitung von fetten Oelen durch 
Pflanzen. Flora, 74 : 300. 

Schroder, H. 

'11. tiber die Selective permeable Hiille des Weizenkornes. Flora, 
102: 186. 

Schulz, Ferdinand. 

'o8. Eine neue Reaktion der Mineralole. Chem. Zeit., 32 : 345 

Shull, Chas. A. 

' i-2- Semi-permeability of Seed Coats. Bot. Gaz., 56: 169. 



VITA 

1873, Oct. 3. Born in Stark County, Illinois. 

1879 — 1887. Attended country school in Penn township, Stark 
County, Illinois. 

1887 — 1 89 1. Time divided between farm and country school, Stark 
County, Illinois. 

1891 — 1892. Student in High School, Bradford, Illinois. 

1892 — 1894. Teacher in country school, Stark County, Illinois. 

1894 — 1896. Student in Illinois State Normal \Jniversity, Normal, 
Illinois. 

1896 — 1897. Principal, Public Schools, Diamond, Illinois. 

1897 — 1899. Student, Illinois State Normal University, Normal, 
Illinois. Graduated 1899. 

1899 — 190 1. Principal, Public Schools, Golconda, Illinois. 

1901 — 1903. Principal, Public Schools, St. Anne, Illinois. 

1903 — 1910. Superintendent, Public Schools, Onarga, Illinois. 

1910 — 1914. Assistant in Botany, University of Illinois. 

Degrees 

191 1. A.B., University of Illinois. 

1912. A.M., University of Illinois. 



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